Knobs for endoscopes with improved usability and ergonomics

ABSTRACT

The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to medical devices and systems with control knobs designed for improved usability and ergonomics. For example, the control knobs of the present disclosure may include surface features for improved gripping, surface features for improved perception of medical device orientation within a patient and/or knobs dimensioned for improved thumb reach and reduced torque.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of priority under 35 U.S.C. §119 to U.S. Provisional Patent Application 62/816,458, filed Mar. 11,2019, which application is incorporated herein by reference in itsentirety for all purposes.

FIELD

The present disclosure relates generally to the field of medicaldevices. In particular, the present disclosure relates to medicaldevices and systems with control knobs designed for improved usabilityand ergonomics.

BACKGROUND

Conventional endoscope handles generally include two control knobs formanipulating the distal tip of the endoscope in the up/down andleft/right directions. The larger of the two control knobs typicallycontrols movement in the up/down directions, while the smaller of thetwo control knobs typically controls movement in the left/rightdirections. Most physicians are trained to hold the endoscope handle intheir left hand and operate the large and small control knobs with theirleft thumb, although some physicians hold the endoscope handle in theirleft hand and operate the large control knob with their left thumb andthe small control knob with their right hand. Each control knobtypically includes a series of evenly spaced crests and troughs, whichthe physician engages with their thumb to rotate the control knob. Manyphysicians have difficulty reaching and rotating one or both controlknobs, especially the small control knob and especially physicians withsmaller hands. This difficulty tends to be compounded if the physicianis required to operate the endoscope in a tortuous position (e.g.,within an extremely curved path within the patient anatomy), a non-idealenvironment (e.g., within the confined space of a particularly smalloperating room or the like), and/or with wet gloves, which tend to slipon the smooth surfaces of the crests and troughs. This difficulty tendsto be further compounded when the endoscope is being manipulated in atortuous body passage due to the strain exerted on the control wiresconnecting the end of the endoscope to the control knobs, which requiresthe physician to exert additional force/torque on the control knobs.Considering that a physician may perform multiple (e.g., 5-10) medicalprocedures per day, each of which may last from less than an hour tomore than 3 hours, the repetitive thumb movement may contribute to longterm discomfort and/or injury to the physician as well as poorer patientoutcomes, e.g., due to increased procedure time, decreased procedureefficiency and/or physician error.

It is with these considerations in mind that a variety of advantageousmedical outcomes may be realized by the devices and systems of thepresent disclosure.

SUMMARY

The present disclosure relates to an endoscopic system comprising acontrol handle operably attached to a proximal end of an endoscope. Afirst control knob may be rotatably attached to the control handle andconfigured to move a distal end of the endoscope in a first direction. Aseries of crests and troughs may define an outer circumference of thefirst control knob. A second control knob may be rotatably attached tothe control handle and configured to move the distal end of theendoscope in a second direction. A series of crests and troughs maydefine an outer circumference of the second control knob. The firstcontrol knob may be disposed between the control handle and the secondcontrol knob. An outer dimension of the first control knob may begreater than a corresponding outer dimension of the second control knob.A gripping surface of the outer circumference of the first control knobmay have a first width and a gripping surface of the outer circumferenceof the second control knob may have a second width. The first width maybe substantially equal to the second width. The gripping surfaces of thefirst and second control knobs may include a textured surface feature.The gripping surfaces of the first and second control knobs may beformed of a material separate from the material of the control knobsand, optionally, co-molded to the outer circumference of the first andsecond control knobs. The first control knob may define a first openingconfigured to receive a first portion of a post of the control handle,and the second control knob may define a second opening configured toreceive a second portion of the post of the control handle. A lever armlength from the center of the first opening to an end of each crest ofthe first control knob may be substantially equal and a lever arm lengthfrom the center of the second opening to an end of each crest of thesecond control knob may be substantially equal. The lever arm length ofeach of the series of crests of the first control knob may beapproximately 35.0 mm. The lever arm length of each of the series ofcrests of the second control knob may be approximately 27.0 mm. Thefirst control knob may define a first opening configured to receive afirst portion of a post of the control handle, and the second controlknob may define a second opening configured to receive a second portionof the post of the control handle. A lever arm length from the center ofthe first opening to an end of each crest of the series of crests of thefirst control knob may be substantially equal. A lever arm length fromthe center of the second opening to an end of a second crest of theseries of crests of the second control knob may be greater than a leverarm length from the center of the second opening to an end of a firstand third crest of the series of crests of the second control knob. Thelever arm length of the second crest of the second control knob may beapproximately 31.0 mm and the lever arm length of the first and thirdcrests of the second control knob may be approximately 29.0 mm. Thelever arm length of each crest of the series of crests of the firstcontrol knob may be approximately 35.0 mm. The second crest of thesecond control knob may be between the first and third crests of thesecond control knob. A lever arm length from the center of the secondopening to an end of a fourth, fifth and sixth crest of the series ofcrests of the second control knob may be less than a lever arm length ofthe first and third crests of the second control knob. The first controlknob may define a first opening configured to receive a first portion ofa post of the control handle, and the second control knob may define asecond opening configured to receive a second portion of the post of thecontrol handle. A lever arm length from the center of the first openingto an end of a second crest of the series of crests of the first controlknob may be greater than a lever arm length from the center of the firstopening to an end of a first and third crest of the series of crests ofthe first control knob. A lever arm length from the center of the secondopening to an end of a second crest of the series of crests of thesecond control knob may be greater than a lever arm length from thecenter of the second opening to an end of a first and third crest of theseries of crests of the second control knob. The lever arm length of thesecond crest of the first control knob may be approximately 39.0 mm andthe lever arm length of the first and third crests of the first controlknob may be approximately 36.0 mm. The lever arm length of the secondcrest of the of the second control knob may be approximately 31.0 mm andthe lever arm length of the first and third crests of the second controlknob may be approximately 29.0 mm. The second crest of the first controlknob may be between the first and third crests of the first controlknob. A lever arm length from the center of the first opening to an endof a fourth and fifth crest of the series of crests of the first controlknob may be less than a lever arm length of the first and third crestsof the first control knob. The second crest of the second control knobmay be between the first and third crests of the second control knob. Alever arm length from the center of the second opening to an end of afourth, fifth and sixth crest of the series of crests of the secondcontrol knob may be less than a lever arm length of the first and thirdcrests of the second control knob. The first control knob may define afirst opening configured to receive a first portion of a post of thecontrol handle, and the second control knob may define a second openingconfigured to receive a second portion of the post of the controlhandle. A lever arm length from the center of the first opening to anend of a first and third crest of the series of crests of the firstcontrol knob may be greater than a lever arm length from the center ofthe first opening to an end of a second crest of the series of crests ofthe first control knob. A lever arm length from the center of the secondopening to an end of a first and third crest of the series of crests ofthe second control knob may be greater than a lever arm length from thecenter of the second opening to an end of a second crest of the seriesof crests of the second control knob. The lever arm length of the firstand third crests of the first control knob may be approximately 38.0 mmand a lever arm length the second crest of the first control knob may beapproximately 35.0 mm. A lever arm length of the first and third crestsof the second control knob may be approximately 32.0 mm and a lever armlength the second crest of the second control knob may be approximately27.0 mm. An outer surface of a first and third crest of the series ofcrests of the first control knob may be substantially smooth, and anouter surface of a second crest of the series of crests of the firstcontrol knob may include an integrated feature. An outer surface of afirst and third crest of the series of crests of the second control knobmay be substantially smooth, and an outer surface of a second crest ofthe series of crests of the second control knob may include anintegrated feature. The second crest of the first control knob may bebetween the first and third crests of the first control knob. The secondcrest of the second control knob may be between the first and thirdcrests of the second control knob.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present disclosure are described by wayof example with reference to the accompanying figures, which areschematic and not intended to be drawn to scale. In the figures, eachidentical or nearly identical component illustrated is typicallyrepresented by a single numeral. For purposes of clarity, not everycomponent is labeled in every figure, nor is every component of eachembodiment shown where illustration is not necessary to allow those ofordinary skill in the art to understand the disclosure. In the figures:

FIGS. 1A-1D and 2A-2C provide perspective views of embodiments of firstand second control knobs of an endoscope handle, according to thepresent disclosure.

FIGS. 3A-3C provide perspective views of embodiments of first and secondcontrol knobs of an endoscope handle, according to the presentdisclosure.

FIGS. 4A-4C provide perspective views of embodiments of first and secondcontrol knobs of an endoscope handle, according to the presentdisclosure.

FIGS. 5A-5D provide perspective views of embodiments of first and secondcontrol knobs of an endoscope handle, according to one embodiment of thepresent disclosure.

DETAILED DESCRIPTION

The present disclosure is not limited to the particular embodimentsdescribed herein. The terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting beyond the scope of the appended claims. Unless otherwisedefined, all technical terms used herein have the same meaning ascommonly understood by one of ordinary skill in the art to which thedisclosure belongs.

Although embodiments of the present disclosure are described withspecific reference to medical devices and systems with control knobsdesigned to provide improved ergonomics and usability of an endoscope(e.g., colonoscopes, duodenoscopes, endoscopic ultrasound (EUS) scopes,etc.), it should be appreciated that a variety of medical devices andsystems may be modified to include such control knobs, including, forexample, stent delivery systems, laparoscopic devices, patientmonitoring systems and the like.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used herein,specify the presence of stated features, regions, steps elements and/orcomponents, but do not preclude the presence or addition of one or moreother features, regions, integers, steps, operations, elements,components and/or groups thereof.

As used herein, the term “distal” refers to the end farthest away fromthe medical professional when introducing a device into a patient, whilethe term “proximal” refers to the end closest to the medicalprofessional when introducing a device into a patient.

Referring to FIGS. 1A-1D, in one embodiment, an endoscopic system 100 ofthe present disclosure may include a control handle 110 operablyattached to a proximal end of an endoscope (not shown). A first controlknob 120 (e.g., which may be larger in diameter than a second controlknob 140, described below) may be rotatably attached to the controlhandle 110 and configured to move a distal end of the endoscope in afirst direction (e.g., up or down). For example, one or more wires(e.g., control wires) may extend along or through a length of theendoscope such that a proximal end of the wire(s) is attached to thefirst control knob and a distal end of the wire(s) is attached to adistal end/distal portion of the endoscope. In various embodiments, thefirst control knob 120 may be rotated in a first direction (e.g.,clockwise) to move the distal end of the endoscope in a first direction(e.g., down), and rotated in a second direction (e.g., opposite, e.g.,counterclockwise) to move the distal end of the endoscope in a seconddirection (e.g., up). A series (e.g., plurality, etc.) of troughs 122and crests 124 a-e may extend around (e.g., define) an outercircumference of the first control knob 120.

A second control knob 140 (e.g., which may be smaller in diameter thanthe first control knob 120) may be rotatably attached to the controlhandle 110 and configured to move the distal end of the endoscope in asecond direction (e.g., left or right). For example, one or more wires(e.g., control wires) may extend along or through a length of theendoscope such that a proximal end of the wire(s) is attached to thesecond control knob and a distal end of the wire(s) is attached to thedistal end/distal portion of the endoscope and rotated in a firstdirection (e.g., clockwise) to move the distal end of the endoscope in afirst direction (e.g., left), and rotated in a second direction (e.g.,counterclockwise) to move the distal end of the endoscope in a seconddirection (e.g., right). A series (e.g., plurality, etc.) of troughs 142and crests 144 a-f may extend around (e.g., define) an outercircumference of the first control knob 120.

In one embodiment, the first control knob 120 may be disposed betweenthe control handle 110 and the second control knob 140, and an outerdimension (e.g., diameter) of the first control knob 120 may be greaterthan a corresponding outer dimension (e.g., diameter) of the secondcontrol knob 140.

In one embodiment, a gripping surface 128 with a first width (e.g.,thickness of the knob in the axial direction along the axis of rotationof the knob) may extend around the outer circumference (e.g., across thetroughs and crests) of the first control knob 120 and a gripping surface148 with a second width (e.g., thickness of the knob in the axialdirection along the axis of rotation of the knob) may extend around theouter circumference (e.g., across the troughs and crests) of the secondcontrol knob 140. The first width and second width may be substantiallyequal. The gripping surfaces 128, 148 may be configured in any desiredmanner for contact by the physician to manipulate the control knobs 120,140. In various embodiments, the gripping surfaces 128, 148 of either orboth of the first and second control knobs 120, 140 may be formed fromor otherwise include a material different from the material of the knob,such as a non-slip material(s) (e.g., soft or compliant polymers/rubber,etc.) to prevent or minimize the finger/thumb of a physician grasping orotherwise applying pressure to the troughs and crests from slipping. Inaddition, or alternatively, a variety of textured surface features(e.g., dimples, depressions, projections, etc.) may be attached to orintegrally formed within the non-slip material(s) to further improvegrip/friction with the finger/thumb of the physician. In variousembodiments, either or both of the gripping surfaces 128, 148 may beattached to the outer circumference of the first and second controlknobs 120, 140 using a suitable glue, adhesive or resin. Alternatively,either or both of the gripping surfaces 128, 148 may be integrallyformed (e.g., co-extruded, co-molded, etc.) with first and secondcontrol knobs 120, 140. It will be appreciated that this feature may beused in conjunction with any of the further features describedhereinafter. In addition, it will be appreciated that the grippingsurfaces 128, 148 may be formed from the same material as that of thecontrol knobs 120, 140, and may be differentiated from the respectivecontrol knobs 120, 140 other than by a difference in material. Forinstance, different textures may be molded into the contact surfaces ofthe control knobs 120, 140 to form the gripping surfaces 128, 148.

Although the troughs 122, 142 and crests 124 a-e, 144 a-f are depictedas uniformly or evenly spaced apart around the circumference of therespective first and second control knobs 120, 140, in variousembodiments, a distance between any or all of the troughs and crests mayvary. In addition, although the first control knob 120 is depicted asincluding five crests, and the second control knob 140 is depicted asincluding six crests, in various embodiments the number of crests ofeach control knob may vary (e.g., fewer than five crests and/or morethan six crests).

Referring to FIG. 1D, in one embodiment, the first control knob 120 maydefine a first opening 130 configured to receive a first portion 114 ofa post 112 (e.g., mounting shaft; FIG. 1C) of the control handle 110,and the second control knob 140 may define a second opening 150configured to receive a second portion 116 of the post 112 of thecontrol handle 110. It will be appreciated that the first opening 130and the second opening 150 may have the same or different diameters.

Referring to FIGS. 2A-2C, in one embodiment, the first opening 130 maybe substantially centered within (e.g., coaxial, geometrically centered,axis of rotation at a geometric center, etc.) the first control knob 120such that a lever arm length (e.g., radius) 132 a-e from the center ofthe first opening 130 to an end of each crest 124 a-e is substantiallyequal. For example, the lever arm length 132 a-e of each crest 124 a-eof the first control knob 120 may be approximately 35.0 mm±2 mm. Inaddition, the second opening 150 may be substantially centered within(e.g., coaxial, geometrically centered, axis of rotation at a geometriccenter, etc.) the second control knob 140 such that a lever arm length(e.g., radius) 152 a-f from the center of the first opening 150 to anend of each crest 144 a-f is substantially equal. For example, the leverarm length 152 a-f of each crest 144 a-f of the second control knob 140may be approximately 27.0 mm±2 mm.

Referring to the embodiment of FIGS. 2A-2C, the torque generated on(e.g., force applied to) a crest 124 a-e of the first control knob 120may be determined using the formula T_(B)=F_(B)×R_(B), where T_(B)represents torque output, F_(B) represents the force applied to a crest124 a-e of the first control knob 120, and R_(B) represents the leverarm length 132 a-e of each crest 124 a-e. Similarly, the torquegenerated on (e.g., applied to) a crest 144 a-f of the second controlknob 140 may be determined using the formula Ts=Fs×Rs, where Tsrepresents torque output, Fs represents the force applied to a crest 144a-f of the second control knob 140, and Rs represents the lever armlength 152 a-f of each crest 144 a-f of a given control knob.

Referring to these formulas, with the lever arm lengths 132 a-e of therespective crests 124 a-e of the first control knob 120 beingsubstantially equal, the torque output (T_(B)) required for thephysician to rotate the first control knob 120 may be substantiallyequal at each crest 124 a-e. Similarly, with the lever arm lengths 152a-f of the respective crests 144 a-f of the second control knob 140being substantially equal, the torque output (Ts) required for thephysician to rotate the second control knob 140 may be substantiallyequal at each crest 144 a-f. Stated differently, none of the crests 124a-e, 144 a-f of the first or second control knobs 120, 140 may providethe physician with a mechanical advantage (e.g., reduced torque outputT_(B), T_(S) to rotate the respective first or second control knobs 120,140) as compared to another one of the crests 124 a-e, 144 a-f.

In use and by way of example, a physician may grasp a control handle 110of an endoscope with their left hand and extend their left thumb tocontact the first and second control knobs 120, 140. In variousembodiments, the physician may realize several advantages whencontacting the gripping surfaces 128, 148 of the first and secondcontrol knobs 120, 140. For example, a substantially equal width of thegripping surface 148 of the second control knob 140 as compared to thewidth of the gripping surfaces 128 of the first control knob 120 mayimprove thumb/finger grip (e.g., reduced or minimize slipping due to wetgloves, etc.) across/along the entire rotation (e.g., outercircumference) of the crests and troughs of the first and second controlknobs 120, 140. In addition, or alternatively, an increased width of thegripping surface 148 of the second control knob 140 may reduce oreliminate the uncomfortable “poking effect” often experienced byphysicians when grasping/contacting thinner crest(s) of a conventionalsecond control knob with a surface of their thumb or finger.

Referring to FIGS. 3A-3C, in one embodiment, the first control knob 120may define a first opening 130 configured to receive a first portion 114of a post 112 (e.g., mounting shaft; FIG. 1C) of the control handle 110,and the second control knob 140 may define a second opening 150configured to receive a second portion 116 of the post 112 of thecontrol handle 110. The first opening 130 may be substantially centeredwithin (e.g., coaxial, geometrically centered, axis of rotation at ageometric center, etc.) the first control knob 120 such that a lever armlength (e.g., radius) 132 a-e from the center of the first opening 130to an end of each crest 124 a-e is substantially equal. For example, thelever arm length 132 a-e of each crest 124 a-e of the first control knob120 may be approximately 35.0 mm. In addition, the second opening 150may be substantially off-center within (e.g., not geometrically centeredwithin, axis of rotation not at a geometric center, etc.) the secondcontrol knob 140 such that a lever arm length 152 b from the center ofthe first opening 150 to an end of a second crest 144 b (e.g., crest B)of the series of crests 144 a-f may be greater than a lever arm lengthfrom the center of the first opening 150 to an end of a first crest 144a (e.g., crest A) and an end of a third crest 144 c (e.g., crest C) ofthe series of crests 144 a-f. For example, the lever arm length 152 b ofthe second crest 144 b may be approximately 31.0 mm±2 mm and a lever armlength 152 a, 152 c of the first and third crests 144 a, 144 c may beapproximately 29.0 mm±2 mm. In one embodiment, the second crest 144 bmay be disposed between the first and third crests 144 a, 144 c. Invarious additional embodiments, a lever arm length from the center ofthe first opening 150 to an end of a fourth crest 144 d (e.g., crest D),fifth crest 144 e (e.g., crest E) and sixth crest 144 f (e.g., crest F)of the series of crests 144 a-f may be less than the lever arm length ofthe first and third crests 144 a, 144 c.

Referring to the embodiment of FIG. 3A-3C, the torque generated on(e.g., applied to) a crest 124 a-e of the first control knob 120 may bedetermined using the formula T_(B)=F_(B)×R_(B), where T_(B) representstorque output, F_(B) represents the force applied to a selected crest124 a-e of the first control knob 120 and R_(B) represents the lever armlength 132 a-e of the selected crest 124 a-e. Similarly, the torquegenerated on (e.g., applied to) a crest 144 a-f of the second controlknob 140 may be determined using the formula Ts_o=Fs_o×Rs_o, where Ts_orepresents torque output, Fs_o represents the force applied to aselected crest 144 a-f of the second control knob 140 and Rs_orepresents the lever arm length 152 a-f of the selected crest 144 a-f.

Referring to these formulas, with the lever arm lengths 132 a-e of therespective crests 124 a-e of the first control knob 120 beingsubstantially equal, the torque output (T_(B)) required for thephysician to rotate the first control knob 120 is substantially equal ateach crest 124 a-e. In comparison, with the second crest 144 b of thesecond control knob 140 having a lever arm length 152 b greater than alever arm length 152 a, 152 c of the first and third crests 144 a, 144 cof the second control knob 140, the torque output (Ts_o) required forthe physician to rotate the second control knob 140 at the second crest144 b may be less than the torque output (Ts_o) required for thephysician to rotate the second control knob 140 at the first or thirdcrests 144 a, 144 c. Similarly, the torque output (Ts_o) required forthe physician to rotate the second control knob 140 at the first orthird crests 144 a, 144 c may be less than the torque output requiredfor the physician to rotate the second control knob 140 at the fourth144 d, fifth 144 e, and sixth 144 f crests (e.g., which have lever armlengths less than the lever arm lengths of the first, second and thirdcrests 144 a-c). As above, none of the crests 124 a-e of the firstcontrol knob 120 may provide the physician with a mechanical advantage(e.g., reduced torque output T_(B) to rotate the first control knob 120)as compared to another one of the crests 124 a-e. In comparison, thetorque output (Ts_o) of the second crest 144 b may provide the physicianwith a mechanical advantage (e.g., reduced torque output Ts to rotatethe second control knob 140) as compared to the torque output (Ts_o) ofthe first and third crests 144 a, 144 c. In other words, the forcerequired by the physician to rotate the second control knob 140 at thesecond crest 144 b is less than the torque to rotate the second controlknob 140 at the first and third crests 144 a, 144 c to achieve the sameor similar torque output from the second control knob 140. Similarly,the torque output (Ts_o) of the first and third crests 144 a, 144 c mayprovide the physician with a mechanical advantage (e.g., reduced torqueoutput Ts to rotate the second control knob 140) as compared to thetorque output (Ts_o) of the fourth 144 d, fifth 144 e and sixth 144 fcrests. It will also be appreciated that the reach to the first, second,and third crests 144 a, 144 b, 144 c of the second control knob 140 ofFIGS. 3A and 3B is generally improved when compared to the first,second, and third crests 144 a, 144 b, 144 c of the second control knob140 of FIGS. 2A and 2B. The maximum lever arm length available to rotatethe knob (the distance from the crest to the axis of rotation) is themaximum radius of the knob at the top of the crest. Offsetting thecenter of rotation results in the knob moving towards the user and thelever arm length increasing. For the same applied force, the torquegenerated to rotate the distal tip of the endoscope increases as thelever arm length increases. Thus, the physician can apply less force tothe control knob of FIGS. 3A and 3B to achieve the same amount of torqueas achieved by the control knob of FIGS. 2A and 2B.

In use and by way of example, a physician may grasp a control handle 110of an endoscope with their left hand and extend their left thumb tocontact the first and second control knobs 120, 140. As described above,the physician may experience difficulty reaching the control knobs,especially the more distant second control knob 140 and especially ifthe physician has small hands. This difficulty may result inover-stretching of the left thumb and/or constant readjustment of theleft hand/left thumb to alternately access the control knobs 120, 140.In various embodiments, the increased lever arm length of the secondcrest 144 b (e.g., as compared to the first and third crests 144 a, 144c) as well as the increased lever arm length of the first and thirdcrests 144 a, 144 c (e.g., as compared to the fourth 144 d, fifth 144 eand sixth 144 f crests), e.g., as may be achieved by moving the centerof rotation of the second control knob 140 away from the geometriccenter, may provide the physician with an improved ability to reach, andreduced torqueing effort to rotate, the second control knob 140. Itshould be appreciated that while the torque output (Ts_o) of the firstand third crests 144 a, 144 c may be greater than the torque output(Ts_o) of the second crest 144 b, the torque output (Ts_o) of the firstand third crests 144 a, 144 c may be less than the torque output (Ts) ofthe corresponding first and third crests of FIGS. 2A-2C (e.g., in whichthe second opening 150 is substantially centered within the secondcontrol knob 140).

Referring to FIGS. 4A-4C, in one embodiment, the first control knob 120may define a first opening 130 configured to receive a first portion 114of a post 112 (e.g., mounting shaft; FIG. 1C) of the control handle 110,and the second control knob 140 may define a second opening 150configured to receive a second portion 116 of the post 112 of thecontrol handle 110. The first opening 130 may be substantiallyoff-center within (e.g., not geometrically centered within, axis ofrotation not at a geometric center, etc.) the first control knob 120such that a lever arm length (e.g., radius) 132 b from the center of thefirst opening 130 to an end of a second crest 124 b (e.g., crest B) ofthe series of crests 124 a-e may be greater than a lever arm length 132a, 132 c from the center of the first opening 130 to an end of a firstcrest 124 a (e.g., crest A) and an end of a third crest 124 c (e.g.,crest C) of the series of crests 124 a-e. For example, the lever armlength 132 b of the second crest 124 b may be approximately 39.0 mm anda lever arm length 132 a, 132 c of the first and third crests 124 a, 124c may be approximately 36.0 mm. In one embodiment, the second crest 124b may be disposed between the first and third crests 124 a, 124 c. Invarious additional embodiments, a lever arm length from the center ofthe first opening 150 to an end of a fourth crest 124 d (e.g., crest D)and fifth crest 124 e (e.g., crest E) of the series of crests 124 a-emay be less than the lever arm length of the first and third crests 124a, 124 c. In addition, the second opening 150 may be substantiallyoff-center within (e.g., not geometrically centered, axis of rotationnot at a geometric center, etc.) the second control knob 140 such that alever arm length 152 b from the center of the first opening 150 to anend of a second crest 144 b (e.g., crest B) of the series of crests 144a-f may be greater than a lever arm length 152 a, 152 c from the centerof the first opening 150 to an end of a first crest 144 a (e.g., crestA) and an end of a third crest 144 c (e.g., crest C) of the series ofcrests 144 a-f. For example, the lever arm length 152 b of the secondcrest 144 b may be approximately 31.0 mm and a lever arm length 152 a,152 c of the first and third crests 144 a, 144 c may be approximately29.0 mm. In one embodiment, the second crest 144 b may be disposedbetween the first and third crests 144 a, 144 c. In various additionalembodiments, a lever arm length from the center of the first opening 150to an end of a fourth crest 144 d (e.g., crest D), fifth crest 144 e(e.g., crest E) and sixth crest 144 f (e.g., crest F) of the series ofcrests 144 a-f may be less than the lever arm length of the first andthird crests 144 a, 144 c.

Referring to the embodiment of FIG. 4A-4C, the torque generated on(e.g., applied to) a crest 124 a-e of the first control knob 120 may bedetermined using the formula T_(B_)o=F_(B_)o×R_(B_)o, where T_(B_)orepresents torque output, F_(B_)o represents the force applied to aselected crest 124 a-e of the first control knob 120 and R_(B_)orepresents the lever arm length 132 a-e of the selected crest 124 a-e.Similarly, the torque generated on (e.g., applied to) a crest 144 a-f ofthe second control knob 140 may be determined using the formulaTs_o=Fs_o×Rs_o, where Ts_o represents torque output, Fs_o represents theforce applied to a selected crest 144 a-f of the second control knob 140and Rs_o represents the lever arm length 152 a-f of the selected crest144 a-f.

Referring to these formulas, with the second crest 124 b having a leverarm length 132 b greater than a lever arm length 132 a, 132 c of thefirst and third crests 124 a, 124 c, the torque output (T_(B_)o)required for a physician to rotate the first control knob 120 at thesecond crest 124 b may be less than the torque output (T_(B_)o) requiredfor the physician to rotate the first control knob 120 at the first orthird crests 124 a, 124 c. Similarly, the torque output (T_(B_)o)required for the physician to rotate the first control knob 120 at thefirst or third crests 124 a, 124 c may be less than the torque outputrequired for the physician to rotate the first control knob 120 at thefourth 124 d and fifth 124 e crests. In addition, with the second crest144 b having a lever arm length 152 b greater than a lever arm length152 a, 152 c of the first and third crests 144 a, 144 c, the torqueoutput (Ts_o) required for the physician to rotate the second controlknob 140 at the second crest 144 b may be less than the torque output(Ts_o) required for the physician to rotate the second control knob 140at the first or third crests 144 a, 144 c. Similarly, the torque output(Ts_o) required for the physician to rotate the second control knob 140at the first or third crests 144 a, 144 c may be less than the torqueoutput required for the physician to rotate the second control knob 140at the fourth 144 d, fifth 144 e and sixth 144 f crests. The torqueoutput (T_(B_)o) of the second crest 124 b may therefore provide thephysician with a mechanical advantage (e.g., reduced torque outputT_(B_)o to rotate the second control knob 140) as compared to the torqueoutput (T_(B_)o) of the first and third crests 124 a, 124 c. Similarly,the torque output (T_(B_)o) of the first and third crests 124 a, 142 cmay provide the physician with a mechanical advantage (e.g., reducedtorque output T_(B_)o to rotate the second control knob 140) as comparedto the torque output (T_(B_)o) of the fourth 124 d and fifth 124 ecrests (e.g., which have lever arm lengths less than the lever armlengths of the first, second and third crests 124 a-c). Similarly, thetorque output (Ts_o) of the second crest 144 b may provide the physicianwith a mechanical advantage (e.g., reduced torque output Ts_o to rotatethe second control knob 140) as compared to the torque output (Ts_o) ofthe first and third crests 144 a, 144 c. Similarly, the torque output(Ts_o) of the first and third crests 144 a, 144 c may provide thephysician with a mechanical advantage (e.g., reduced torque output Ts torotate the second control knob 140) as compared to the torque output(Ts_o) of the fourth 144 d, fifth 144 e and sixth 144 f crests (e.g.,which have lever arm lengths less than the lever arm lengths of thefirst, second and third crests 144 a-c).

In use and by way of example, a physician may grasp a control handle 110of an endoscope with their left hand and extend their left thumb tocontact the first and second control knobs 120, 140. In variousembodiments, the increased lever arm length 132 b of the second crest124 b (e.g., as compared to the first and third crests 124 a, 124 c) aswell as the increased lever arm length 132 a, 132 c of the first andthird crests 124 a, 124 c (e.g., as compared to the fourth 124 d andfifth 124 e crests), e.g., as may be achieved by moving the center ofrotation of the first control knob 120 off-center (e.g., away fromgeometric center), may provide the physician with an improved ability toreach, and reduced torqueing effort to rotate, the first control knob120. In various additional embodiments, the increased lever arm length152 b of the second crest 144 b (e.g., as compared to the first andthird crests 144 a, 144 c) as well as the increased lever arm length 152a, 152 c of the first and third crests 144 a, 144 c (e.g., as comparedto the fourth 144 d, fifth 144 e and sixth 144 f crests), e.g., as maybe achieved by moving the center of rotation of the second control knob140 off-axis (e.g., away from the geometric center), may provide thephysician with an improved ability to reach, and reduced torqueingeffort to rotate, the second control knob 140. It should be appreciatedthat while the torque output (T_(B_)o) of the first and third crests 124a, 124 c may be greater than the torque output (T_(B_)o) of the secondcrest 124 b, the torque output (T_(B_)o) of the first and third crests124 a, 124 c may be less than the torque output (T_(B), T_(B_)o) of thecorresponding first and third crests of FIGS. 2A-2C and/or FIGS. 3A-3C(e.g., in which the second opening 150 is substantially centered withinthe second control knob 140). It should also be appreciated that whilethe torque output (Ts_o) of the first and third crests 144 a, 144 c maybe greater than the torque output (Ts_o) of the second crest 144 b, thetorque output (Ts_o) of the first and third crests 144 a, 144 c may beless than the torque output (Ts) of the corresponding first and thirdcrests of FIGS. 2A-2C (e.g., in which the second opening 150 issubstantially centered within the second control knob 140).

Referring to FIG. 5A, in one embodiment, the first control knob 120 maydefine a first opening 130 configured to receive a first portion 114 ofa post 112 (e.g., mounting shaft; FIG. 1C) of the control handle 110,and the second control knob 140 may define a second opening 150configured to receive a second portion 116 of the post 112 of thecontrol handle 110. The first and second openings 130, 150 may besubstantially centered within (e.g., coaxial, geometrically centered,axis of rotation at a geometric center, etc.) the first and secondcontrol knobs 120, 140. In one embodiment, a lever arm length 132 a, 132c from the center of the first opening 130 to an end of a first crest124 a (e.g., crest A) and an end of a third crest 124 c (e.g., crest C)of the series of crests 124 a-e may be greater than a lever arm length132 b from the center of the first opening 130 to an end of a secondcrest 124 b (e.g., crest B) of the series of crests 124 a-e. Forexample, the lever arm length 132 b of the second crest 124 b may beapproximately 35.0 mm and a lever arm length 132 a, 132 c of the firstand third crests 124 a, 124 c may be approximately 38.0 mm. In oneembodiment, a lever arm length 152 a, 152 c from the center of the firstopening 150 to an end of a first crest 144 a (e.g., crest A) and an endof a third crest 144 c (e.g., crest C) of the series of crests 144 a-fmay be greater than a lever arm length 152 b from the center of thefirst opening 150 to an end of a second crest 144 b (e.g., crest B) ofthe series of crests 144 a-f. For example, the lever arm length 152 b ofthe second crest 144 b may be approximately 27.0 mm and a lever armlength of the first and third crests 144 a, 144 c may be approximately32.0 mm. In another example, the lever arm length 152 b of the secondcrest 144 b may be approximately 32.0 mm and a lever arm length of thefirst and third crests 144 a, 144 c may be approximately 27.0 mm.

Referring to the embodiment of FIG. 5A, the torque generated on (e.g.,applied to) a crest 124 a-e of the first control knob 120 may bedetermined using the formula T_(E_B)=F_(E_B)×R_(E_B), where T_(E_B)represents torque output, F_(E_B) represents the force applied to aselected crest 124 a-e of the first control knob 120 and R_(E_B)represents the lever arm length 132 a-e of the selected crest 124 a-e.Similarly, the torque generated on (e.g., applied to) a crest 144 a-f ofthe second control knob 140 may be determined using the formulaT_(E_S)=F_(E_S)×R_(E_S), where T_(E_S) represents torque output, F_(E_S)represents the force applied to a selected crest 144 a-f of the secondcontrol knob 140 and R_(E_S) represents the lever arm length 132 a-e ofthe selected crest 144 a-f.

Referring to these formulas, with the first and third crests 124 a, 124c having a lever arm length 132 a, 132 c greater than a lever arm length132 b of the second crest 124 b, the torque output (T_(E_B)) requiredfor the physician to rotate the first control knob 120 at the first orthird crest 124 a, 124 c may be less than the torque output (T_(E_B))required for the physician to rotate the first control knob 120 at thesecond crest 124 b. In other words, the force required by the physicianto rotate the second control knob 140 at the first and third crests 144a, 144 c is less than the torque to rotate the second control knob 140at the second crest 144 b to achieve the same or similar torque outputfrom the second control knob 140. In addition, with the first and thirdcrests 144 a, 144 c having a lever arm length 152 a, 152 c greater thana lever arm length 152 b of the second crest 144 b, the torque output(T_(E_S)) required for the physician to rotate the second control knob140 at the first and third crests 144 a, 144 c may be less than thetorque output (T_(E_S)) required for the physician to rotate the secondcontrol knob 140 at the second crest 144 b. The first and third crests124 a, 124 c of the first control knob 120 may therefore provide thephysician with a mechanical advantage (e.g., reduced torque outputT_(E_S) to rotate the first control knob 120) as compared to the torqueoutput of crests 124 b, 124 d and/or 124 e. Similarly, the torque output(T_(E_S)) of the first and third crests 144 a, 144 c may provide thephysician with a mechanical advantage (e.g., reduced torque outputT_(E_S) to rotate the second control knob 140) as compared to the torqueoutput of crests 144 b and/or 144 d-f.

In use and by way of example, a physician may grasp a control handle 110of an endoscope with their left hand and extend their left thumb tocontact the first and second control knobs 120, 140. In variousembodiments, the increased lever arm length of the first and third crest124 a, 124 c (e.g., as compared to the second crests 124 b), achieved byextending the length of the first and third crests 124 a, 124 c, mayprovide the physician with an improved ability to reach, and reducedtorqueing effort to rotate, the first control knob 120 when engaging thefirst or third crests 124 a, 124 c. In various additional embodiments,the increased lever arm length of the first and third crests 144 a, 144c (e.g., as compared to the second crest 144 b) achieved by extendingthe length of the first and third crests 144 a, 144 c may provide thephysician with an improved ability to reach, and reduced torqueingeffort to rotate, the second control knob 140 when engaging the first orthird crests 144 a, 144 c. In various embodiments, the lever arm lengthsof crests 124 a, 124 c, 144 a, 144 c may provide the physician with themaximum mechanical advantage when the distal tip of the endoscope isbent or angled at or near its maximum functional limit and thereforerequire the maximum amount of force/torque to move the distal tip (e.g.,up/down and left/right).

In one embodiment, an outer surface of the first crests 124 a, 144 a andan outer surface of the third crests 124 c, 144 c of the respectivefirst and second control knobs 120, 140 may be substantially smooth orotherwise different from an outer surface of the second crests 124 b,144 b of the respective first and second control knobs 120, 140, whichmay include an integrated surface feature 134, 154 (e.g., dimples,raised lines, projections, etc.) to provide tactile feel/feedback to thephysician. Conversely, an outer surface of the first crests 124 a, 144 aand an outer surface of the third crests 124 c, 144 c of the respectivefirst and second control knobs 120, 140 may include an integratedsurface feature, while the outer surface of the second crests 124 b, 144b of the respective first and second control knobs 120, 140 may besmooth or otherwise different. It will be appreciated that any or all ofthe crests 124 a-e, 144 a-f may include an integrated surface feature134, 154 to provide tactile feel/feedback to the physician.

As will be understood by those of skill in the art, the position of apatient on an operating table may vary (e.g., prone, semi-prone, supine,etc.) depending on the physician's preference, the layout of thesurgical suite and/or the medical procedure being performed. Thesevaried patient positions often result in the endoscope being advanced toa target location along a complex three-dimensional path. Physicianstypically advance/manipulate the endoscope within the patient by relyingon a three-dimensional video image provided by a camera located at thedistal end of the endoscope and a two-dimensional fluoroscopic image.The two-dimensional fluoroscopic image often makes it difficult for thephysician to track and/or determine the three-dimensional orientation ofthe distal end of the endoscope and/or the portion of the endoscopeshaft extending behind the camera, thereby leading to potentialconfusion between up/down movement (e.g., using the first control knob)and left/right movement (e.g., using the second control knob).

In various embodiments, the tactile feel provided by the integratedsurface features 134, 154 on the second crests 124 b, 144 b of the firstand second control knobs 120, 140 may allow the physician todetermine/identify the relative location of the first and second crests124 b, 144 b, and therefore the three-dimensional orientation of thedistal end and/or distal portion of the endoscope, without lookingdirectly at the control handle 110 and away from the video monitorand/or fluoroscopic image. As outlined below, the physician may thenrotate the first and/or second control knobs 120, 140 to preciselymanipulate the distal end/distal portion of the endoscope inthree-dimensions. For example, referring to FIG. 5A, with the secondcrests 124 b, 144 b of the first and second control knobs 120, 140aligned (e.g., in the neutral position; knob position “I”) the distaltip of the endoscope is in a straight configuration, with the profile ofthe endoscope shaft in a single plane and without any substantial strainor torque. Referring to FIG. 5B, with the first and second control knobsin the “I” position, the first control knob 120 may be rotated down(e.g., counterclockwise) such that the second crest 124 b of the firstcontrol knob is aligned with the first crest 144 a of the second controlknob 140 (e.g., knob position “J”). With the first and second controlknobs in the “J” position, the distal end of the endoscope may move upand with the profile of the endoscope shaft in a single plane. Referringto FIG. 5C, with the first and second control knobs in the “J” position,the second control knob 140 may then be rotated up (e.g., clockwise)such that the second crest 144 b of the first control knob is alignedwith the fourth crest 124 d of the second control knob 140 (e.g., knobposition “K”). With the first and second control knobs in the “K”position the distal end of the endoscope may move to the right.Referring to FIG. 5D, with the first and second control knobs in the “K”position, the second control knob 140 may then be rotated down (e.g.,counterclockwise; knob position “L”) such that the first crest 124 a ofthe first control knob 120 is aligned with the first crest 144 a of thesecond control knob 140. With the first and second control knobsreturned to the “L” position the distal end of the endo scope may moveup and to the left.

In various embodiments, the first and second control knobs 120, 140 ofthe various embodiments depicted in FIGS. 1A-5D may provide a variety ofadvantages as compared to conventional endoscope handle control knobs.For example, the first and second control knobs may provide improvedergonomics and ease-of-use for a physician to rotate and/or maintain theposition of the distal end of an endoscope within a patient. Improvedcontrol of distal tip movement of the endoscope may also decreasemedical procedure times and/or increase efficiency, with beneficialresults realized by both the patient (e.g., improved procedure outcome)and the physician (e.g., shorter procedure times leading to reducedfatigue, etc.). In addition, because different types of endoscopes(e.g., duodenoscopes, EUS scopes, colonoscopes, etc.) typically includethe same knob interfaces (e.g., mounting shafts), the first and/orsecond control knobs 120, 140 disclosed herein may be readilyincorporated onto any endoscope handle. The ability of the control knobsto be used interchangeably (e.g., in various combinations of theembodiments outlined above), may provide improved adaptability amongphysicians with different hand sizes and/or operating preferences.

In various embodiments, any or all of the components of the controlknobs 120, 140 disclosed herein may be formed from (e.g., injectionmolded, co-extruded) or otherwise include a variety of rigidthermoplastic polymers that are resistant to various disinfecting orsterilizing modalities (e.g., chemicals, radiation, U.V. light),including, for example, polycarbonate, ABS, nylon, glass-reinforcednylon, acetal acrylic, PEET, PEEK, Pebax, polypropylene and the like.

In various embodiments, the lever arm length(s) of any crest(s) of thefirst or second control knobs are exemplary and can be varied inrelation to each other to optimize ergonomics for a particular desiredapplication. In addition, or alternatively, force may be applied to anyside, edge or surface of any of the troughs and/or crests of the firstand second control knobs from any direction (e.g., pushing with thethumb on top of a crest, pushing with a finger on a slope of the crest,etc.)

All of the devices and/or methods disclosed and claimed herein can bemade and executed without undue experimentation in light of the presentdisclosure. While the devices and methods of this disclosure have beendescribed in terms of preferred embodiments, it may be apparent to thoseof skill in the art that variations can be applied to the devices and/ormethods and in the steps or in the sequence of steps of the methoddescribed herein without departing from the concept, spirit and scope ofthe disclosure. All such similar substitutes and modifications apparentto those skilled in the art are deemed to be within the spirit, scopeand concept of the disclosure as defined by the appended claims.

What is claimed is:
 1. An endoscopic system, comprising: a controlhandle operably attached to a proximal end of an endoscope; a firstcontrol knob rotatably attached to the control handle via a firstopening of the first control knob and configured to move a distal end ofthe endoscope in a first direction; a series of crests and troughsdefining an outer circumference of the first control knob; a secondcontrol knob rotatably attached to the control handle via a secondopening of the second control knob and configured to move the distal endof the endoscope in a second direction; a series of crests and troughsdefining an outer circumference of the second control knob, wherein alever arm length from a center of the second opening to an end of asecond crest of the series of crests of the second control knob isgreater than each of a lever arm length from the center of the secondopening to an end of a first crest and a third crest of the series ofcrests of the second control knob, and each of the lever arm lengthsfrom the center of the second opening to the ends of the first crest andthe third crest is greater than each of a lever arm length from thecenter of the second opening to ends of a fourth crest, a fifth crest,and a sixth crest of the series of crests of the second control knob;wherein the first control knob is disposed between the control handleand the second control knob; wherein an outer dimension of the firstcontrol knob is greater than an outer dimension of the second controlknob; and wherein a gripping surface of the outer circumference of thefirst control knob includes a first width and a gripping surface of theouter circumference of the second control knob includes a second width.2. The endoscopic system of claim 1, wherein the gripping surfaces ofthe first and second control knobs include a textured surface feature.3. The endoscopic system of claim 1, wherein the first width issubstantially equal to the second width.
 4. The endoscopic system ofclaim 1, wherein the first opening of the first control knob isconfigured to receive a first portion of a post of the control handle,and the second opening of the second control knob is configured toreceive a second portion of the post of the control handle; and whereina lever arm length from a center of the first opening to an end of eachcrest of the series of crests of the first control knob is substantiallyequal.
 5. The endoscopic system of claim 4, wherein the lever arm lengthof each of the series of crests of the first control knob isapproximately 35.0 mm.
 6. The endoscopic system of claim 1, wherein thelever arm length from the center of the second opening to the end of thesecond crest of the second control knob is approximately 31.0 mm, andthe lever arm length from the center of the second opening to the end ofeach of the first crest and the third crest of the second control knobis approximately 29.0 mm.
 7. The endoscopic system of claim 1, whereinthe second crest of the second control knob is between the first crestand the third crest of the second control knob.
 8. The endoscopic systemof claim 1, wherein the first opening of the first control knob isconfigured to receive a first portion of a post of the control handle,and the second opening of the second control knob is configured toreceive a second portion of the post of the control handle; and whereina lever arm length from a center of the first opening to an end of asecond crest of the series of crests of the first control knob isgreater than each of a lever arm length from the center of the firstopening to an end of a first crest and a third crest of the series ofcrests of the first control knob.
 9. The endoscopic system of claim 8,wherein the lever arm length from the center of the first opening to theend of the second crest of the first control knob is approximately 39.0mm, and the lever arm length from the center of the first opening to theend of each of the first crest and the third crest of the first controlknob is approximately 36.0 mm, and wherein the lever arm length from thecenter of the second opening to the end of the second crest of thesecond control knob is approximately 31.0 mm, and the lever arm lengthfrom the center of the second opening to the end of each of the firstcrest and the third crest of the second control knob is approximately29.0 mm.
 10. The endoscopic system of claim 8, wherein the second crestof the first control knob is between the first crest and the third crestof the first control knob.
 11. The endoscopic system of claim 8, whereina lever arm length from the center of the first opening to an end of afourth crest and a fifth crest of the series of crests of the firstcontrol knob is less than the lever arm length from the center of thefirst opening to the first crest and the third crest of the firstcontrol knob.
 12. The endoscopic system of claim 8, wherein the secondcrest of the second control knob is between the first crest and thethird crest of the second control knob.
 13. The endoscopic system ofclaim 1, wherein the first opening of the first control knob isconfigured to receive a first portion of a post of the control handle,and the second opening of the second control knob is configured toreceive a second portion of the post of the control handle; and whereina lever arm length from a center of the first opening to an end of eachof a first crest and a third crest of the series of crests of the firstcontrol knob is greater than a lever arm length from the center of thefirst opening to an end of a second crest of the series of crests of thefirst control knob.
 14. The endoscopic system of claim 13, wherein thelever arm length from the center of the first opening to the end of eachof the first crest and the third crest of the first control knob isapproximately 38.0 mm, and the lever arm length from the center of thefirst opening to the end of the second crest of the first control knobis approximately 35.0 mm.
 15. The endoscopic system of claim 1, whereinan outer surface of each of a first crest and a third crest of theseries of crests of the first control knob is substantially smooth, andan outer surface of a second crest of the series of crests of the firstcontrol knob includes an integrated feature; and wherein an outersurface of each of the first crest and the third crest of the series ofcrests of the second control knob is substantially smooth, and an outersurface of the second crest of the series of crests of the secondcontrol knob includes an integrated feature.
 16. The endoscopic systemof claim 15, wherein the second crest of the first control knob isbetween the first crest and the third crest of the first control knob;and wherein the second crest of the second control knob is between thefirst crest and the third crest of the second control knob.
 17. Anendoscopic system, comprising: a control handle operably attached to aproximal end of an endoscope; and a control knob rotatably attached tothe control handle via an opening of the control knob and configured tomove a distal end of the endoscope in a direction; wherein: an outercircumference of the control knob is defined by a plurality of radiallyoutermost points, including first, second, third, fourth, and fifthradially outermost points; a lever arm length extends from a center ofthe opening to an end of each of the plurality of radially outermostpoints, each of a first lever arm length of the first radially outermostpoint and a third lever arm length of the third radially outmost pointis different than a second lever arm length of the second radiallyoutermost point, and each of a fourth lever arm length of the fourthradially outermost point and a fifth lever arm length of the fifthradially outmost point is less than the first, second, and third leverarm lengths.
 18. An endoscopic system, comprising: a control handleoperably attached to a proximal end of an endoscope; and a control knobrotatably attached to the control handle via an opening of the controlknob and configured to move a distal end of the endoscope in adirection; and wherein an outer circumference of the control knob isdefined by a plurality of radially outermost points each associated witha lever arm length from a center of the opening to the respectiveradially outermost point, and the opening of the control knob isoff-center within the control knob resulting in at least three differentlever arm lengths associated with the plurality of radially outermostpoints.
 19. The endoscopic system of claim 18, wherein the plurality ofradially outermost points include at least first, second, and thirdradially outermost points, and a second arm length associated with thesecond radially outermost point is greater than each of a first leverarm length associated with the first radially outermost point and athird lever arm length associated with the third radially outermostpoint.
 20. The endoscopic system of claim 18, wherein the plurality ofradially outermost points include at least first, second, and thirdradially outermost points, and a second arm length associated with thesecond radially outermost point is less than each of a first lever armlength associated with the first radially outermost point and a thirdlever arm length associated with the third radially outermost point.